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Commit 0bc392ee authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Steven Rostedt
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tracing: Change tracing_entries_fops to rely on tracing_get_cpu() 

tracing_open_generic_tc() is racy, the memory inode->i_private
points to can be already freed.

1. Change its last user, tracing_entries_fops, to use
   tracing_*_generic_tr() instead.

2. Change debugfs_create_file("buffer_size_kb", data) callers
   to pass "data = tr".

3. Change tracing_entries_read() and tracing_entries_write() to
   use tracing_get_cpu().

4. Kill the no longer used tracing_open_generic_tc() and
   tracing_release_generic_tc().

Link: http://lkml.kernel.org/r/20130723152606.GA23730@redhat.com



Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 4d3435b8

kernel/trace/trace.c

+12 −37
Original line number Diff line number Diff line
@@ -2984,23 +2984,6 @@ static int tracing_open_generic_tr(struct inode *inode, struct file *filp) 
	return 0;

}



static int tracing_open_generic_tc(struct inode *inode, struct file *filp)

{

	struct trace_cpu *tc = inode->i_private;

	struct trace_array *tr = tc->tr;



	if (tracing_disabled)

		return -ENODEV;



	if (trace_array_get(tr) < 0)

		return -ENODEV;



	filp->private_data = inode->i_private;



	return 0;

	

}



static int tracing_release(struct inode *inode, struct file *file)

{

	struct seq_file *m = file->private_data;
@@ -3054,15 +3037,6 @@ static int tracing_release_generic_tr(struct inode *inode, struct file *file) 
	return 0;

}



static int tracing_release_generic_tc(struct inode *inode, struct file *file)

{

	struct trace_cpu *tc = inode->i_private;

	struct trace_array *tr = tc->tr;



	trace_array_put(tr);

	return 0;

}



static int tracing_single_release_tr(struct inode *inode, struct file *file)

{

	struct trace_array *tr = inode->i_private;
@@ -4382,15 +4356,16 @@ static ssize_t 
tracing_entries_read(struct file *filp, char __user *ubuf,

		     size_t cnt, loff_t *ppos)

{

	struct trace_cpu *tc = filp->private_data;

	struct trace_array *tr = tc->tr;

	struct inode *inode = file_inode(filp);

	struct trace_array *tr = inode->i_private;

	int cpu = tracing_get_cpu(inode);

	char buf[64];

	int r = 0;

	ssize_t ret;



	mutex_lock(&trace_types_lock);



	if (tc->cpu == RING_BUFFER_ALL_CPUS) {

	if (cpu == RING_BUFFER_ALL_CPUS) {

		int cpu, buf_size_same;

		unsigned long size;
@@ -4417,7 +4392,7 @@ tracing_entries_read(struct file *filp, char __user *ubuf, 
		} else

			r = sprintf(buf, "X\n");

	} else

		r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, tc->cpu)->entries >> 10);

		r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);



	mutex_unlock(&trace_types_lock);
@@ -4429,7 +4404,8 @@ static ssize_t 
tracing_entries_write(struct file *filp, const char __user *ubuf,

		      size_t cnt, loff_t *ppos)

{

	struct trace_cpu *tc = filp->private_data;

	struct inode *inode = file_inode(filp);

	struct trace_array *tr = inode->i_private;

	unsigned long val;

	int ret;
@@ -4443,8 +4419,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, 


	/* value is in KB */

	val <<= 10;



	ret = tracing_resize_ring_buffer(tc->tr, val, tc->cpu);

	ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));

	if (ret < 0)

		return ret;
@@ -4892,11 +4867,11 @@ static const struct file_operations tracing_pipe_fops = { 
};



static const struct file_operations tracing_entries_fops = {

	.open		= tracing_open_generic_tc,

	.open		= tracing_open_generic_tr,

	.read		= tracing_entries_read,

	.write		= tracing_entries_write,

	.llseek		= generic_file_llseek,

	.release	= tracing_release_generic_tc,

	.release	= tracing_release_generic_tr,

};



static const struct file_operations tracing_total_entries_fops = {
@@ -5580,7 +5555,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) 
				tr, cpu, &tracing_stats_fops);



	trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,

				&data->trace_cpu, cpu, &tracing_entries_fops);

				tr, cpu, &tracing_entries_fops);



#ifdef CONFIG_TRACER_SNAPSHOT

	trace_create_cpu_file("snapshot", 0644, d_cpu,
@@ -6156,7 +6131,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) 
			  tr, &tracing_pipe_fops);



	trace_create_file("buffer_size_kb", 0644, d_tracer,

			(void *)&tr->trace_cpu, &tracing_entries_fops);

			  tr, &tracing_entries_fops);



	trace_create_file("buffer_total_size_kb", 0444, d_tracer,

			  tr, &tracing_total_entries_fops);